Nitrogen-inflated tires were first introduced for use on professional race cars, since their tires normally have a wider surface area and generate more friction and heat during use. Traditional compressed-air tires had trouble withstanding the extreme heat build-up and pressure changes during races, and it was determined that introducing nitrogen provided improved heat dissipation, handled high speeds more efficiently, and regulated high internal tire temperatures without combusting. Now, nitrogen-filled tires are commonly seen on planes, professional racing vehicles, modern passenger vehicles, and some car dealerships may even offer to fill your tires with nitrogen for an added cost. Most vehicles that are factory-equipped with nitrogen in the tires have bright green caps on the valve stems as an indicator to use nitrogen instead of compressed air. If you are wondering if you should fill your car’s tires with nitrogen, don’t rely solely on what you read online; a good rule of thumb is to keep your tires inflated with the same gas that was used to inflate them from the factory. Be sure to also consult your owners manual to find what type of air your tires need.
There is no difference in the tires used for compressed air and nitrogen-inflated applications, and the tires are not specifically designed for the use of a specific gas. The only variable in the tires for either application is the gas that is used to fill the tire itself. So how are regular tires and nitrogen-filled tires different? In short, it’s the chemical makeup of the two gasses. Compressed air is approximately 78% nitrogen, 21% oxygen, and contains traces of water vapor and other gasses – exactly the same as the air in our atmosphere. Nitrogen-filled tires are inflated with 100% pure nitrogen, which requires a specific nitrogen compressor to ensure purity. Oxygen is a gas that can expand and contract significantly with temperature changes, but the additional nitrogen concentration limits the effects of temperature fluctuations on tires filled with only nitrogen. This means that tires filled with nitrogen are better at handling changes in temperature, and are less likely to have some characteristics of tires filled with compressed air, like low tire pressure in the winter. It’s important to note that nitrogen-filled tires are not immune to pressure changes: on average, nitrogen loses one PSI for every 10°F drop, and compressed air loses one to two PSI for every 10°F, meaning that pure nitrogen in tires can often withstand extreme environments longer without leaking or experiencing low tire pressure. Overall, nitrogen helps maintain a more stable tire pressure and does not leak as easily as compressed air-filled tires, leaving the driver with more dependable traction and pressure when driving at high speeds.
Longer Tire Life
In terms of chemistry, nitrogen is a “bigger” gas molecule than oxygen; this slight chemical difference makes it harder for air to leak from your tires. Nitrogen gas escapes car tires less easily thanks to its ability to maintain its chemical structure without breaking down. Oxygen molecules have two paired electrons, meaning that in the case of temperature fluctuations, oxygen is more likely to break apart by transferring electrons to maintain stability. Nitrogen has half-filled orbitals, and is more likely to remain intact despite temperature changes. Compressed air, on the other hand, has less nitrogen content, heats up faster, and is more likely to escape from tires than pure nitrogen. The slight difference in nitrogen concentrations between nitrogen-filled tires and compressed air-filled tires can dramatically impact the tires’ ability to hold air pressure despite temperature changes. Since compressed air-filled tires do not contain as much nitrogen as pure nitrogen-filled tires, air is also more likely to escape regular tires and can result in an illuminated TPMS light. Not only can low tire pressure cause a TPMS light to appear on your dashboard, but it also increases the chances of tire damage.
Deflated tires have more contact with the pavement due to their increased surface area, and with this, create more friction, heat, and are more likely to experience accelerated or abnormal tread wear. Over-inflated tires can sustain more damage to the center of the tire tread, as too much air pressure can cause the tire to bulge and result in a smaller portion of the center of the tread contacting the ground. This can not only result in tire damage, but may cause your wheels to bounce and can increase overall braking time due to a lack of contact and traction. Learn more about how tire pressure can affect your vehicle with our helpful article.
Since nitrogen is a more stable gas that experiences less impact due to temperature variations, it helps protect tires from going flat and experiencing wear. By avoiding air leaks and keeping your tires consistently inflated to the appropriate pressure levels, tires filled with nitrogen can prevent flats or sidewall bulging that could lead to premature tire damage.
Improved Fuel Economy
Because your tires lose less air thanks to nitrogen’s chemical structure, you may also see an increase in fuel economy by filling your tires with nitrogen. Low tire pressure levels can negatively affect fuel mileage, as the tires effectively have a flat spot and are slightly out of round. This requires more power to turn the wheel and tire to move your vehicle. By maintaining healthy tires at the right pressure levels, your vehicle can get better mileage — and the pressure consistency of nitrogen-filled tires can help prevent variations in fuel economy due to temperature fluctuations.
Increased Safety
Nitrogen-filled tires can also make your drives safer by increasing consistency and dependability. Tires that are not inflated to the appropriate internal pressure run the risk of not making complete tread contact with the road surface. An underinflated tire may actually dip slightly in the middle of tread, which can cause your tire to maintain fewer points of contact. Overinflated tires may bulge in the center of the tread, also causing a loss of road contact and traction and increasing tire wear. Not only can the more consistent pressures of nitrogen improve keep your tire inflated to the right pressure for a longer period of time, but nitrogen does not combust; this means that in the case of a car collision and subsequent fire, your vehicle does not have an added chance of fire or explosion that may be seen with compressed-air tires.
If your vehicle was equipped with nitrogen-filled tires from the factory, or if you have made the switch from compressed air to nitrogen in your tires, it is important to keep your tires inflated to the manufacturer’s specifications. As discussed earlier, no matter if your tires are filled with regular compressed air or nitrogen, keeping your tires at their recommended pressure level can help prolong their life, improve fuel economy, and perform as you expect. Find nitrogen fill stations near you to maintain the right tire pressure in your vehicle and prevent costly damage so you can drive with confidence.